Hi Maxeymommy,
Hope you had a happy Mother's Day!* Your plant looks like seedlings.* The photo is small and it appears there is only one set of true leaves so it's difficult to say what they are.* A couple of plants that come to mind are some type of Chrysanthemum or even flat leaved parsley.* It looks like they need more sun as the stems are long and spindly.** I would say to water when the top inch of the soil is dry.* You can put your finger in the soil up to the first knuckle* When there are a couple more leaves take another picture.* When there are two sets of true leaves I would suggest you pot them up separetly.
Newt
When weeding, the best way to make sure you are removing a weed and not a valuable plant is to pull on it. If it comes out of the ground easily, it is a valuable plant.